reranker-cohere

Introduction

• The reranker-cohere module enables reranking search results using Cohere reranking.
• This module uses a third-party API and may incur costs. Make sure to check the Cohere pricing page before applying reranking to large amounts of data.
• You will need a Cohere API key. You can request one here.

Related pages

• How-to search: Rerank

How to enable

Weaviate Cloud Services

This module is enabled by default on the WCS.

Weaviate open source

Add reranker-cohere to the ENABLE_MODULES environment variable.

Below is an example Docker Compose file, which will spin up Weaviate with the reranker-cohere module (as well as text2vec-cohere).

---
version: '3.4'
services:
  weaviate:
    command:
    - --host
    - 0.0.0.0
    - --port
    - '8080'
    - --scheme
    - http
    image: semitechnologies/weaviate:1.21.4
    restart: on-failure:0
    ports:
     - "8080:8080"
    environment:
      QUERY_DEFAULTS_LIMIT: 20
      AUTHENTICATION_ANONYMOUS_ACCESS_ENABLED: 'true'
      PERSISTENCE_DATA_PATH: "./data"
      DEFAULT_VECTORIZER_MODULE: text2vec-cohere
      ENABLE_MODULES: text2vec-cohere,reranker-cohere
      COHERE_APIKEY: $COHERE_APIKEY
      CLUSTER_HOSTNAME: 'node1'
...

note

• You can also use the Weaviate configuration tool to create a Weaviate setup with this module.
• The COHERE_APIKEY environment variable is optional and the client can instead provide the key at insert/query time as an HTTP header (see the 'usage' section for instructions)

Schema configuration

The reranker-cohere module can be configured for any class in the schema. You can also specify options such as the model to use.

This example configures the Document class to use the reranker-cohere module, with the rerank-multilingual-v2.0 model, and to return the documents in the response.

{
  "classes": [
    {
      "class": "Document",
      ...,
      "moduleConfig": {
        "reranker-cohere": {
            "model": "rerank-multilingual-v2.0",
        },
      }
    }
  ]
}

Reranker selection

If there is only one reranker module enabled, you don't need to do anything. The reranker module will be used by default.

Where multiple reranker modules are enabled, you must specify the reranker module to be used for each class. You can do this by adding the desired reranker in the moduleConfig section of the schema, even without any further settings.

Set reranker for a class

{
  "classes": [
    {
      "class": "Document",
      ...,
      "moduleConfig": {
        "reranker-cohere": {},  // This will configure the 'Document' class to use the 'reranker-cohere' module
      }
    }
  ]
}

Model selection

The reranker-cohere module supports the following models:

• rerank-english-v2.0
• rerank-multilingual-v2.0

Usage

API key

• If the COHERE_APIKEY environment variable is not set, clients can set the API key at query time by adding this HTTP header: X-Cohere-Api-Key: YOUR-COHERE-API-KEY.

Queries

• Using this module will enable the rerank GraphQL _additional property.
• For usage examples, see the Howto: Search - Reranking page.

More resources

For additional information, try these sources.

1. Frequently Asked Questions
2. Weaviate Community Forum
3. Knowledge base of old issues
4. Stackoverflow
5. Weaviate slack channel